a. Field of the Invention
This invention relates to circuit protection devices and related control systems.
b. Related Art
A step-type voltage regulator is a device which is used to maintain a relatively constant voltage level in a power distribution system. Without such a regulator, the voltage level of the power distribution system could fluxuate significantly and cause damage to electrically powered equipment.
A conventional step-type voltage regulator transformer assembly 102 and its associated controller 106 are shown in FIG. 1. The voltage regulator can be, for example, a Siemens JFR series. The windings and other internal components that form the transformer assembly 102 are mounted in an oil filled tank 108. A tap changing mechanism (not shown) is commonly sealed in a separate chamber in the tank 108.
The various electrical signals generated by the transformer are brought out to a terminal block 110 and external bushings S, SL, L for access. The terminal block is preferably covered with a waterproof housing. An indicator 112 is provided so that the position of the tap as well as its minimum and maximum positions can be readily determined.
A cabinet 114 is secured to the tank to mount and protect the voltage regulator controller 106. The cabinet 114 includes a door (not shown) and is sealed in a manner sufficient to protect the voltage regulator controller 106 from the elements. Signals carried between the transformer or tap changing mechanism and the voltage regulator controller 106 are carried via an external conduit 116.
In order for the voltage regulator transformer assembly 102 and the controller 106 to work together to maintain the proper line characteristics, the controller is commonly provided with the specifications of the transformer assembly 102. For example, information such as the transformer assembly's voltage rating, current rating, configuration and impedance characteristics may be programmed into the controller. Statistical information such as number of tap changes and temperature extremes may also be maintained by the controller so that a field engineer can determine when to change or service the voltage regulator.